Role of guided FNA in gallbladder cancer: A retrospective 3-year study

Background: A majority of the patients with gall bladder cancer (GBCa) present at an advanced stage and have poor survival. The aim is to retrospectively study the role of guided FNA in the diagnosis of GBCa in a superspecialty institute and to describe the cytomorphologic spectrum of gall bladder (GB) lesions in the North Indian population. Materials and Methods: All suspected cases of GBCa who underwent guided FNA from the primary GB mass or metastatic liver space-occupying lesion from 2017 to 2019 were included. The aspirate smears were retrieved and analyzed for cytomorphological features independently by two cytopathologists. The neoplastic lesions were classified according to the WHO 2019 classification. Results: Of 489 cases, fine needle aspiration cytology (FNAC) was diagnostic in 463 cases (94.6%), of which 417 (90.1%) were positive for malignancy, 35 (7.5%) were inflammatory, and 11 (2.4%) were inconclusive for malignancy. Adenocarcinoma not otherwise specified (NOS) was the most common type seen in 330 cases (79.1%) and 87 (20.9%) were unusual variants. These included papillary adenocarcinoma (22, 5.2%), mucinous adenocarcinoma (12, 2.8%), signet ring carcinoma (2,0.4%), adenosquamous carcinoma (8, 1.9%), squamous cell carcinoma (10, 2.4%), neuroendocrine neoplasms (7, 1.7%), undifferentiated carcinoma (24, 5.7%) and non-Hodgkin lymphoma (2,0.4%), respectively. Immunohistochemistry on the cell block confirmed the diagnosis wherever possible. Histopathology was discordant in 5 out of 33 cases. Conclusion: Guided FNAC is a sensitive investigation that plays a crucial role in confirming the diagnosis and deciding the further treatment options in advanced-stage GBCa patients. The uncommon variants of GBCa can be reliably categorized on cytology.